Effect of ausforming and cooling condition on the orientation relationship in martensite and bainite of low carbon steels

A method to determine the orientation relationship (OR) in bainitic and martensitic transformations has been employed that does not use reconstruction of prior austenite grains. It is shown that the method keeps accuracy regardless of orientation non-uniformity induced inside austenite grains by hot deformation. The revealed OR behavior for bainite formed under continuous cooling agrees with its temperature dependence previously found in case of isothermal transformation. Ausforming effect on the OR detected in martensite is presumably due to deformation induced subgrains separated by low-angle dislocation boundaries.